SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I am in the process of planning the rest of my sprinkler system and need a little help. I currently have 3 zones working and will finishing off the yard very soon.

I have a well as my water source and the gauge indicates that the pump turns on at 40psi and shuts off at 60psi. I measured my flow after 1 of the valves previously using the 5 gallon bucket method. It took 13.5 seconds to fill. The system is also plumbed with 1" poly. Both the bucket method and the max capacity of 1" poly indicate about 13GPM system capacity.

My back yard plan currently indicates that I will need 12 PGP rotors with the spacing head-to-head about 26-30 feet apart. First question is should I use 2 or 3 zones? Also should I just assume 45psi to be conserative when calculating what Nozzle to use and the resulting GPM?

Here is the breakdown of 1 6 head zone.
Degree of
Rotor Coverage Nozzle GPM
1 90 2 0.9
2 90 2 0.9
3 90 2 0.9
4 180 5 1.8
5 360 7 3.4
6 360 7 3.4
------
11.3 GPM Capacity

This is under my 13 GPM capacity so I think I will be fine. The numbers are from the hunter PGP rotor spec sheet. I assumed 30 ft radius and 45 psi pressure and rounded up when in between.

How do you account for the bigger nozzles throwing the water farther at a lower presssure? A number 7 nozzle is approx 41 ft. at 45 psi but I only need 30 ft. I assume you use pressure since it should be independant of the nozzle.

Also, the pressure I am using is inside the house at the pressure switch. How much loss can I expect assuming 1" pipe and 1 master valve(also backflow preventer) and Irritol 2400T valve?

Any help would be greatly appreciated. I think I have a handle on this but only want to do it once.

Also, can you mix pgp and pgm heads in the same zone since they are both rotors?

Thanks in Advance,
Greg

So I guess I should start over and recalculate my GPM.

Is it best to go and buy the Toro Flow and Pressure gauge? Where can I get one? I don't see it in the online store.

Or can I go and buy a pressure gauge like used by my pump pressure switch and build one with a shutoff value to control the pressure (open to 35-40 PSI) and then meausure how long it takes to fill the bucket.

Thanks in Advance,
Greg

I couldn't find a toro flow gauge so I made my own. I used a 1" tee and connected a pressure gauge to it. Then connected a 1" shutoff to that to control the pressure. Then ran the water into a 5 gallon bucket and measured the amount of time to fill it.

The reading are taken on a zone that I have the valve finished for but still need to finish burying the pipe. So the water is passing through the master valve/back flow preventer and a 2400T valve.

Here are the results.

PSI PSI Time GPM
(gauge) (pump)
40 Note 1 55 5.4
30 50 41 7.3
20 44 33 9.0
15 40 30 10
10 37 30 10
Full Open 31 30 10

Note 1: At 40 psi the pump was able to keep up and would get to 60 psi and shut off. The turn on also seems a little low and is set at 35psi. Should I change this to 40 psi. Will it impact the life of the pump?

I can't explain the difference between the full open time of 13.5 sec I saw in the spring and the 30 sec I measured today. The only difference is that I manually opened the 2400T today and previously I let the controller open the valve. I don't have the extra pcm-300 modules for the Hunter ProC controller and it get confusing switching the wires around, so I figured I would just disable zone 3 by disconnected the wire and connect it to ground. Then I could turn on zone 3 which would only turn on the master valve. Then I could manually turn on the valve I was testing with.

I was hoping for a little more flow as it looks like I will need most of the capacity of my ProC controller for the grass and was hoping to have some zones for flower gardens.

I hope this isn't to confusing. Thanks for the patience and any help will be greatly appreciated.

I new I had registered previously. I just couldn't remember the username. To avoid any confusion, cdig04 and gravunder are the same person(me). Thanks in Advance, Greg

I went to the local hardware store that does a lot of sprinkler installs in the area and he got me started. Bought the ProC controller, master valve/backflow preventer, poly pipe, heads, etc. The front yard is pretty small. I use 4 PGP heads with only 90 degree usage for each head. Then I have the front bushes/flowers which only has 3 hunter SRS sprays heads. The 3rd zone is the north side of the house and used 4 ps spray heads. None of the zones tax the system very heavily. The backyard is much larger, where I need to actually break the areas into zones.

I should go and find out what type of master valve/back flow preventer I have. It doesn't say much on the valve. I will try to include a picture at the bottom.

I am trying not to keep asking the hardware store questions as they are very expensive for most of there sprinkler stuff and feel a little guilty since I will be getting the rest of my stuff from sprinkler warehouse. PGP heads are $20 each.

I just want to make sure I am designing the zones so the pump starts at the beginning and doesn't cycle while watering.

Thanks in Advance,
Greg
<img src="file:///d:\mastervalve.jpg" border=0>